#include "my_stdio.h"
#include <string.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>

mFILE *mfopen(const char *filename, const char *mode)
{
 int fd = -1;
 if(strcmp(mode, "r") == 0)
 {
 fd = open(filename, O_RDONLY);
 }
 else if(strcmp(mode, "w")== 0)
 {
 fd = open(filename, O_CREAT|O_WRONLY|O_TRUNC, 0666);
 }
 else if(strcmp(mode, "a") == 0)
 {
 fd = open(filename, O_CREAT|O_WRONLY|O_APPEND, 0666);
 }
 if(fd < 0) return NULL;
 mFILE *mf = (mFILE*)malloc(sizeof(mFILE));
 if(!mf) 
 {
 close(fd);
 return NULL;
 }
 mf->fileno = fd;
 mf->flag = FLUSH_LINE;
 mf->size = 0;
 mf->cap = SIZE;
 return mf;
}

void mfflush(mFILE *stream)
{
 if(stream->size > 0)
 {
 // 写到内核文件的文件缓冲区中! 
 write(stream->fileno, stream->outbuffer, stream->size);
 // 刷新到外设 
 fsync(stream->fileno);
 stream->size = 0;
 }
}
int mfwrite(const void *ptr, int num, mFILE *stream)
{
 // 1. 拷贝
 memcpy(stream->outbuffer+stream->size, ptr, num);
 stream->size += num;
 // 2. 检测是否要刷新 
 if(stream->flag == FLUSH_LINE && stream->size > 0 && stream->outbuffer[stream->size-1]== '\n')
 {
 mfflush(stream);
 }
 return num;
}
void mfclose(mFILE *stream)
{
 if(stream->size > 0)
 {
 mfflush(stream);
 }
 close(stream->fileno);
}

